Boiler



Sept. 15, 1959 D. E. PENNING BOILER Filed March 19, 1958 M. T m m l l l l l l I I l I l I l I l l l l 1 l l l l I l l ll Ll IIIIIIILT United States Patent comm Douglas E. Penning, Titusville, Pa., asslgnor to Struthers Wells Corporation, Titusville, Pa., a corporation of Maryland Application March 19, 1958, Serial No. 722,606 3 Claims. (Cl. 122-149) This invention relates to boilers, and particularly to boilers of the type commonly known as wet back.

The novel features of the boiler reside in the construction thereof wherein an outer cylindrical shell is provided with a firebox and fire tubes running longitudinally therein. A transverse wall forwardly of the rear end of the shell serves as a tube header and terminus for the firebox while a double wall jacket extends from the transverse wall, adjacent the vertical mid portion thereof, rearwardly and downwardly to the rear of the outer shell to define a water jacket around a rear chamber with which the firebox and certain of the fire tubes communicate. The bottom portion of the transverse wall constitutes the front wall of the rear chamber. The construction results in a remaining chamber or space above the rear chamber but within the outer shell serving as a flue chamber with which other fire tubes communicate or as an insulating chamber. With this con- 2,904,015 Patented Sept. 15, 1959 "ice ' plate 8, throughout its entire extent, extends transversely struction a complete flue or insulating chamber may be provided by merely covering the upper portion of the rear end of the shell with a light gauge metal sheet.

It is therefore an object of this invention to provide a boiler construction incorporating a wet back feature of simple yet economical design.

It is another object of this invention to provide a boiler construction having a wet back feature particularly suited to cooperate with a flue chamber all within the confines of a single outer shell.

Further and additional objects and advantages will become apparent as the description proceeds in connection with the accompanying drawings, wherein:

Fig. 1 is a longitudinal vertical sectional view through a boiler illustrating the principles of the present invention; a

Fig. 2 is a vertical sectional view taken substantially along the line 22 of Fig. l; and

Fig. 3 is an end view, wherein the right half is in elevation with parts broken away, and the left half is in vertical section along the line 3-3 of Fig. l.

The boiler construction illustrated in the drawings is considerably simplified in that many connections, couplings, hand holes, fittings and the like, along with stay bolts and similar details have been omitted for the purpose of simplifying the illustration.

A boiler constructed in accordance with the present invention comprises an outer generally cylindrical sheet metal shell 2 having a front wall or header 4. The rear edge 6 of the shell 2 defines the rearmost portion of the boiler as will be described later. Within the shell 2 and forwardly of the rearmost edge 6, the boiler is provided with a transverse wall or plate 8 extending downwardly to a point slightly above the center of the shell. The wall 8 then extends rearwardly and downwardly to define a curved portion 10 extending to a plane substantially coincident with the rear edge 6 of the shell 2. The lower portion of the plate 8 extends downwardly in the described plane and is welded or otherwise sealed to the periphery of the shell 2 to define a rear lower end wall into contact with the inner surface or end edge of the shell 2 and is welded, riveted, or-otherwise secured and sealed to the shell to define, forwardly thereof, a water chamber 14. Substantially coplanar with the upper portion of the plate 8 is a further header or plate 16. The periphery of the plate 16 is spaced from the shell 2 and the plate 8 to define a peripheral passageway 44 in communication with the water chamber 14. Acap structure I or shell comprising a generally semicylindrical portion 18 and another portion 20 is secured at its open edge to the plate 16 and extends in spaced, generally parallel relationship to the rearwardly bulged portion of plate 10 and the lower half of shell 2 to define a rear chamber 22. From the structurethus far described, it will be obvious that the rear chamber 22 is completely surrounded by water from chamber 14 when the boiler is in operation.

An access opening for chamber 22 is defined by a tubular fitting 24 and a rear cap or closure 26.

A generally cylindrical firebox 28 extends through the front plate 4 and through plate 16 into communication with the rear chamber 22 just described. A suitable fuel burning apparatus (not shown). is intended to be mounted in the forward end of the firebox 28 to introduce fuel and air thereto for combustion and the production of hot gases.

By referring to Fig. 2 it will be seen that a plurality of fire tubes 30 extend longitudinally throughthe chamber 14, front plate 4 and plate 16 generally laterally alongside the firebox 28. The uppermost of the tubes 30 are at substantially the level of the top of firebox 28. As is obvious, the fire tubes 30 also communicate with the interior of chamber 22. A further group of fire tubes 32 is arranged to extend longitudinally through the water chamber 14, front plate 4'and the upper portion of plate 8, thuscommunicating with the space above the curved portion 10 of plate 8. At the forward end of the boiler a cap structure 34 defines a reversing chamber 36 of the general shape indicated in Fig. 2. The chamber 36 receives hot gases moving forwardly through the fire tubes 30 and directs those gases into the forward ends of the fire tubes 32, in a well-known manner.

It is to be noted that the upper portion of plate 8 is spaced forwardly from the rear edge 6 of the shell 2 defininga space or chamber 38 above the chamber 22. A cover plate 40 of generally semicircular outline, is suitably secured at its periphery to the rear edge 6 of the shell 2 and to the upper part of portion 12 of wall 8 to thus completely enclose the space 38 and to define a closed flue chamber. A suitable stack 42 communicates with the interior of the flue chamber 38 and serves to dispose of flue gases.

In the description heretofore, the upper portion of plate 8 and plate 16 have been referred to as two separate elements. However, it is obvious that the upper portion of plate 8 and plate 16 may be considered as being a single transverse wall through the shell having a slot 44 therein defining a passageway providing communication between the water chamber 14 and the space 46 between walls 10 and 20 and between wall 18 and shell 2. The portions 10 and 12 of plate 8 along with the rear lower portion of the shell 2 may be considered as an outer cap structure overlying the rear end of the firebox 28 and fire tubes 30 and the walls 18 and 20 may be considered to be a further cap structure inwardly of and spaced from the cap structure defined by portions 10 and 12.

In operation it will be obvious that hot gases produced by combustion of fuel in the firebox 28 will move rearwardly therethrough and heat the walls thereof to transfer heat to water in the chamber 14. Thus hot gases move rearwardly into chamber 22 from whence they are deflected into the rear ends of fire tubes 30. The gases then move forwardly through fire tubes 30 into chamber 36, then rearwardly through fire tubes 32 into flue chamber 38 and out the stack 42.

Die terms. semicylindrical and semicircular, as used herein, are not intended to limit the described structures to the suggested proportions. For example, the chambers 22 and 38 could be difierently proportioned by having the chamber 22 extend high enough to enclose the ends of fire tubes 32 and thus form a 2-pass boiler. In such a case the'chamber 38 serves as an insulating chamber ratherthan a flue chamber.

While a single specific embodiment of the invention is shown and described herein, it is to be noted that the same is merely illustrative of the principles of the invention, which encompasses other modifications falling within the scope of the appended claims.

I claim:

1. In a boiler construction, an outer shell, a transverse wall within said shell spaced inwardly of the rear end thereof and comprising separate substantially coplanar plates spaced apart at their adjacent edges and one of said plates being spaced from said shell throughout its periphery, an open-ended firebox extending through said inner cap wall and spaced therefrom and having a portion joined to the rear portion of said shell and to the 4 edge of said other plate adjacent said one plate, said inner and outer cap walls and said portion of said shell defining therebetween a water chamber communicating at the edges of said one plate with the interior of said shell, the remainder of the space within said shell rearwardly of the other plate constituting a chamber, and further fire tubes extending through said shell and said other plate into said chamber.

2. In a boiler construction, a generally horizontal cylindrical shell having a rear end wall and a transverse wall spaced inwardly from said end wall and comprising an upper plate secured to said shell and a lower plate spaced from said upper plate and spaced from said shell throughout its periphery, a further wall extending rearwardly from the lower edge of said upper plate to said rear wall and dividing the space rearwardly of said transverse wall into a lower chamber and an upper chamber, a cap wall in said lower chamber secured to the periphery of said lower plate and spaced inwardly from said further wall, rear wall and shell, and defining therewith a double-walled rear chamber, a firebox extending longitudinally through said shell and lower wall and communicating with the interior of said rear chamber, a first group of fire tubes extending longitudinally through said shell and lower wall and communicating with said rear chamber, and a second group of fire tubes extending longitudinally through said shell and upper wall and communicating with said upper chamber.

3. A boiler construction as defined in claim 2 including chamber defining means at the front end of said boiler enclosing and providing communication between the front ends of said first and second groups of fire tubes.

Williams May 21, 1929 Welter Sept. 19, 1933 

